Method of testing a liquid sample, a test unit, and an automatized system of a plurality of test units

ABSTRACT

A method of testing a liquid sample, a test unit, an and automatized system of a plurality of test units. The system is for large scale testing patient blood samples, comprising a large number of test units at different locations and connected through a common control unit. In an individual test unit there is a liquid dosing chamber, hermetically closed packages of calibrator and control liquids, closed liquid reagent packages, a liquid sample inlet and an actuator for dosing and mixing the reacting components and elements for registering results from the reactions. The test unit can calibrate, control and test reactions automatically under surveillance of the control unit. The system can use the same packaged liquids in each of the test units, enabling calculation of averages of the control results and, through comparison of individual results with an average, letting faults be detected through results outside permitted deviations.

The invention relates to a method of testing a liquid sample, especiallyin the field of biochemical and clinical chemistry to test blood-basedsamples derived from patients for various diseases or other healthconditions. Further objects of the invention are a test unit forcarrying out the method of the invention, as well as a system comprisinga plurality of test units at various locations subjected to centralizedautomatic operation through a data transmitting network ofcommunications.

The general aim of the invention is to improve quality control ofchemical, biochemical and clinical laboratory testing. The most frequenttesting type is known as In-Vitro-Diagnostics (IVD). Most IVD tests areperformed on the serum or plasma, derived from the bloods sample of thepatient. The test results are compared to values simultaneously (˜sameday) obtained from the known control serum samples. The provided controlvalue now is typically not a single concentration but a rather widerange, reflecting the uncertainty accumulated in the traceability duringthe instrument manufacturing process, during manufacturing process ofthe control serum and in the control values of the final patientmeasurement. A number of factors are presently contributing to theuncertainty of the control serum product.

The general problem associated with any serum, including the controlserum, is that serum is a very good medium for microbes and fungus torapidly grow and spoil the serum whenever exposed to ambientcircumstances. The present laboratory practice in the device level takesplace by pipetting between open control serum cups and other analysissteps. Control serum bottles must be opened to transfer part of it as acontrol sample. Whenever the serum control bottle is opened to theatmosphere, it is sown with microbial and fungi contamination.Additionally there are powerful chemical effects and reactivity withinserum components themselves, changing concentrations over time. Even ifthe opened serum bottle is stored in 2-8 degrees C. in a refrigerator,it has typically one week working time. If the serum bottle is notopened, the working time is 2 months. In a frozen state at −20 degreesthe unopened the control serum preserves typically 30 months.

The classical method to extend the working time of the control serum isto preserve it in a dry form, without any liquid water, whereby a properstorage is not a problem. Freeze-drying the control serum and dividingit in so small portions that it can be used at once, the same day, ispresently the most common practice. The user needs to reconstitute thecontrol serum by adding the specified small amount of water andcarefully dissolve the dry serum into a homogenous solution. Thedrawback of this method is that the user needs to dispense veryaccurately the very small amount of pure water and dissolve the contentinto a homogenous solution. In manufacturing there are a number ofproduction and control steps in manufacturing small control sera inmini/micro bottles. Those production steps are monitored and processcontrolled so that gross errors are detected. The calibration by the enduser at patient work level has least means of finding out when makinggross errors in reconstitution of very small volumes. When the finaluser is a layman from the laboratory profession standpoint like inPoint-Of-Care testing, the patient safety is jeopardized when dependingon such a quality control of IVD tests. This is the reason whereby moreexpensive ready-to-use liquid sera provide higher quality but require aprofessional laboratory management.

In principle a control serum product aims to be traceable to value froma high-level reference laboratory. To accurately measure the values ofall tens and hundreds of specified test compounds, requires special,tedious and so expensive reference methods and instruments, onlyavailable in few reference laboratories. Quality traceability standardISO 17511:2003 describes steps from a reference laboratory via multiplesteps in the manufacturing to the final calibration of the patientsample in the field. There are approximately ten steps. Each step isadding variation to the traceability from the reference laboratoryvalue, totalling up to many percent as standard deviation. That is farfrom satisfactory from quality traceability standpoint. IVDmanufacturers are transferring expensive reference calibration materialsto their research laboratories, to act as a yardstick for calibratingmanufacturing instruments and for calibrating controlling sera productsin manufacturing. Every analyser yields a somewhat different result,between manufacturers and even within of different models of the samemanufacturer.

To prevent the drift in control values between instruments andmanufacturers to carry too far over time and so to jeopardize patientsafety, joint external quality assurance organizations have been formedto monitor reproducibility among laboratories. The quality organizationis sending the same unknown serum sample once or twice a year for eachparticipant in the quality ring for analysis. Quality organization isstatistically summarizing all test results and reports to eachparticipant, how far from the average they are with each of theiranalysers, in comparison to all others having the same analyser. Nostand is taken if the mean test value is right or wrong. It only tellswhere other laboratories are on average and how high is the standarddeviation. Thus obtained feedback may take over a year, being eithergrossly off from others or in the middle of other laboratories using thesame analyser model. In practice it is the responsibility of anattending physician to compare the laboratory IVD data to the clinicalpicture of the patient and not to solely trust unexpected laboratorydata. Unexpected results may result from many artefact sources, startingfrom a faulty or wrong sample, from errors in calibration or from aspoiled reagent of the test or from analyser drift. Unexpected resultsindicate retesting, delays in patient care and inefficiencies inlaboratory services. Origin of this uncertainty is resulting from a longchain and deteriorated traceability of testing quality, wherebydetection of other sources of variation is shielded by the poortraceability and variability of calibration.

Many chemical, biochemical and clinical laboratory tests use suchsensitive reagents and other analytical steps that the analyzer and thetest method should be tested one or more times a day with a known testsample, called as quality control process. Traceability of qualityrelates to tracing back the accuracy of the quality control sample viamanufacturers production and quality control processes to the values ofthe reference laboratory with reference methods. The present qualityprocedure assumes a laboratory environment and professional skills. Thepresent practice in quality traceability contains about 10 steps, eachadding variability, yielding only the range for a true value.

Working time of liquid reagents with 12-18 months are available e.g. byJAS Diagnostics, Miami, Fla. and elsewhere. Reagents for its parts wouldenable a full automation and remove the need of a laboratory to managereagents. But the quality control rules require a control sample everyday or even after every 8 hours, presently only well done withlaboratory skills in laboratory environment. Before efficiency byautomation can really advance, the problem of quality control andtraceability needs to be resolved without need of professional skills.

The invention provides a solution to the problem through improvement andautomatization of the quality control and quality traceability of IVDtests, performed in the test units on the field outside the laboratory,that is at Point-Of-Care sites and in other non-laboratory placeswithout professional laboratory skills. The outcome of the invention inits wholeness is, that the quality and traceability part of IVD testingis delivered and monitored professionally but remotely all the time, sothat the users can be non-professionals. Ensuring high quality ofpatient test data with lesser or no amount of laboratory skills is asignificant advantage of the invention. Furthermore, the inventionenables real time monitoring, adjusting and controlling the quality ofthe networked analyzers in the field using the inventive method. Theinvention also enables tracing and adjusting the changes in the controlmaterial, so dynamically monitoring traceability, thus extending theunattended working time of calibration from hours to months.

The method of testing a liquid sample according to the invention uses atest unit comprising a liquid dosing chamber, the method beingcharacterized by

-   -   provision of at least one closed calibrator liquid package        connected to the dosing chamber through an openable valve,    -   provision of at least one hermetically closed control liquid        package connected to the dosing chamber through an openable        valve, the control liquid differing from the calibrator liquid,    -   provision of at least one inlet with an openable valve for at        least one liquid reagent,    -   provision of an inlet with an openable valve for the liquid        sample to be tested,    -   performing at separate stages calibrating, control and test        reactions between the calibrator liquid, control liquid and the        liquid sample, respectively, and at least one liquid reagent,    -   each stage comprising opening the respective valves and sucking        predetermined amounts of the reacting liquids to the dosing        chamber to produce the respective reaction,    -   cleaning the dosing chamber between the reactions,    -   registering the results of the calibrating, control and test        reactions, and    -   by comparison of said results obtaining a test result for the        liquid sample.

A test unit for testing a liquid sample according to the invention ischaracterized in that it comprises a liquid dosing chamber,

-   -   at least one closed calibrator liquid package connected to the        liquid dosing chamber through an openable valve,    -   at least one hermetically closed control liquid package        connected to the liquid dosing chamber through an openable        valve,    -   at least one openable inlet for at leat one liquid reagent,    -   an openable inlet for a liquid sample to be tested,    -   an actuator for sucking amounts of said calibrator liquid, said        control liquid, said liquid sample and/or said at least one        liquid reagent to the liquid dosing chamber at different stages,        to perform calibrating, control and test reactions,        respectively, and    -   means for registering and comparing the results of the reactions        to obtain a test result.

The test unit according to the invention preferably further comprises atleast one closed liquid reagent package connected to the liquid dosingchamber through an openable valve. The liquid reagent is combined in thedosing chamber with the calibrator liquid, the control liquid or theliquid sample for performing the calibrating, control or testsreactions, respectively. The liquids may be sucked to the liquid dosingchamber by means of the actuator, which may be a bellows, a pump or aninjector.

Furthermore, the test unit according to the invention may comprise anopenable and closable inlet for filling the liquid dosing chamber withdilution liquid. The test unit according to the invention may alsocomprise an openable and closable outlet for sucking dilution liquidfrom the liquid dosing chamber. The dosing chamber would be filled withthe dilution liquid before the above-mentioned sucking operations fordosing the liquids needed for the reactions. Dosing of the reactiveliquids would then take place by sucking corresponding amounts of thedilution liquid from the dosing chamber. Preferably, there is a commoninlet/outlet for both the filling and sucking purposes.

As an example, the calibrating reaction performed in the test unit couldinclude the following sequence of steps:

-   -   provision of a closed calibrator liquid package connected to a        liquid dosing chamber of the test unit through an openable        valve,    -   provision of at least one closed reagent liquid package        connected to the liquid dosing chamber through an openable        valve,    -   filling the liquid dosing chamber with dilution liquid,    -   sucking an amount of calibrator liquid from the package to the        liquid dosing chamber by opening the respective valve and        sucking a corresponding amount of dilution liquid from the        liquid dosing chamber,    -   sucking an amount of the at least one reagent liquid from the        respective package to the liquid dosing chamber by opening the        respective valve and sucking a corresponding amount of dilution        liquid from the liquid dosing chamber,    -   performing the reaction between the calibrator liquid and the at        least one reagent liquid as combined in the liquid dosing        chamber, and    -   registering the result of the reaction for use as a reference in        performing the corresponding reaction with a liquid sample to be        tested.

As noted, the filling and sucking steps are preferably carried outthrough a common inlet/outlet by means of an actuator connectedtherewith.

The control and test reactions could be performed in an analogousmanner, the control liquid in a closed control liquid package and thetest sample supplied from an inlet with a closable valve replacing thecalibrator liquid, respectively.

The calibrator and control liquid packages, as well as the reagentpackages, are preferably hermetically sealed collapsible bags with adiminishing volume as liquid is sucked therefrom. Such bags aredescribed in the patent publication U.S. Pat. No. 4,588,554, which ishereby incorporated by reference in the present specification.

The control liquid used in the invention when applied to diagnosticalpurposes is preferably blood serum. The calibrator liquid may be a purecomponent of blood serum dissolved in a solvent.

The calibrator and control liquids are preferably preserved in the bagsin frozen condition before use for their respective purposes in the testunit. The test unit can be equipped with a refrigerator as well as withheating means for selectively thawing the liquids to be sucked to theliquid dosing chamber.

There may be a separate reaction chamber or space connected through anopenable valve with the dosing chamber. Sensors are provided either inthe dosing chamber or reaction chamber or space to detect the results ofthe reactions.

The entire test unit and its functions may generally correspond to thosedescribed in the publication WO 02/061395 A1, which is herebyincorporated by reference in the present specification. However, thereference does not disclose the combined calibration and controloperations, which are essential for the present invention. The test unitof the reference comprises reagent bags designated in FIG. 2 byreference character 10, which according to the present invention wouldalso comprise at least one bag containing a calibrator liquid and atleast one bag containing a control liquid.

A system according to the invention containing a plurality of test unitsfor testing liquid samples as defined above is characterized in thateach test unit is equipped for performing the same test reaction, thatthe test units are differently located and each connected through datatransmission communications to a common control unit monitoring the testunits in the system by data transmitted through said communications,that the reaction with the control liquid is performed in each test unitat predetermined time intervals to obtain individual control values forthe test units, an average of said control values of all the test unitsis determined, the individual control values are compared to saidaverage, and only test units with a reference value within a permitteddeviation from the average are approved for performance of the reactionwith samples to be tested.

A further system according to the invention, containing a plurality oftest units for testing liquid samples as defined above, is characterizedin that each test unit is equipped for performing the same testreaction, that the test units are differently located and each connectedthrough data transmission communications to a common control unitmonitoring the test units in the system by data transmitted through saidcommunications, that the performance of said test system is from time totime independently evaluated by an accurate analysis of control andcalibrator liquid reference samples preserved in circumstancescorresponding to those prevailing in the test units, to estimate andadjust the time effect on calibrator and on control liquids and onreagents stored in the test units.

Preferably a system according to the invention comprises both sets offeatures as recited above simultaneously. This is to say thatcalibration of the system is carried out under the direction of thecontrol unit, the analysis of the reference samples being performed in acommon laboratory, while the controls at relatively short timeintervals, daily or even more frequently, are performed under automaticdirection and monitoring by the control unit.

In the system each test unit has at least one accurately knowncalibrator liquid and/or at least one accurately known control liquidand at least one test reagent, which is the same in each test unit.Preferably the calibrator liquids, control liquids and reagents are thesame, i.e. derived from the same manufacturing batches, in each testunit in the system. In such a case all the calibration and controlresults received from the individual test units are comparable, andaverages can be calculated for each of them to be used in comparisons.

In case that in a test units a reference value outside the permitteddeviation from the average is obtained, the reaction with the controlliquid may be repeated at the request of the control unit one or moretimes to exclude the possibility of a random error, so that the controlunit can approve previous and subsequent test results.

The method of the invention, the test unit using the method, and thequality monitoring system comprising said test units can be summarizedas follows:

1. The method comprises use of liquid control serum without everfunctionally opening its package and so not shortening its working timewhen virtually preserved as unopened.

2. The basic device to exercise the invention corresponds functionallyto a hermetic valve connecting the hermetic calibrator serum package tothe liquid processing part, i.e. a dosing or reaction chamber, of ananalyzer.

3. The system comprises monitoring the said inventive calibrationdevices, i.e. the test unit, and calibration functions in the field viaa network, working in real time from the calibration standpoint andsecures that only proper values are used even when the calibrationvalues of the used control sera are changing over time.

This invention eliminates variability effects and a short working timeof manual handling and exposing control sera and calibrators to ambientatmosphere, in connection of testing patient samples. The virtualunopenness for a long working time and hydraulic accuracy andreliability in key liquid processing enables full automation so that aplurality of test units, all loaded with the same, known high qualitycontrol sera, calibrators and reagents, can be networked under a commoncontrol unit, for an automatic co-monitoring the quality data. When anerror is detected, repeated readings of control tests are automaticallyperformed to exclude random errors. If repeated controls can not resolvethe detected problem, then the same test is automatically performed witha stable calibrator. If the result is the same as before, control serumis bad. If the test result is changed and the controlserum test isproportionally changed, the control serum is good and the test reagentis bad. Furthermore, the automatic co-monitoring of the common controlunit allows an automatic, real time, high precision evaluation of a truestability or drift sera and of control reagents as a standard error ofmeans of test data from plurality of test units. The high precision ofmeasured average values from a plurality of test units allows morereliable testing than gives a short term, nominally stable control orcalibrator with given wide error margins. As summary, the major cost andquality benefit of the invention is, that the errors, time delays andcosts relating manual laboratory work is eliminated and the statisticalreliability from real time quality related data from plurality of testunits provides superior security in quality.

A more detailed description of the various aspects and steps of thepreferred embodiment of the invention is:

-   -   1. Calibration of a large lot of control serum at a high        accuracy level    -   2. Packaging the serum in hermetic, air-free, collapsible        packages, e.g. such as described in U.S. Pat. No. 4,588,554, so        that liquid can be taken out without anything going in and        freezing the packages for longer term storage. Further, a        sterile filtering in filling, removing air or oxygen will reduce        spoiling.    -   3. Installing one or more frozen control serum packages into a        test unit to cover the capacity and working time of the rest of        the system. One of the packages is automatically melted and made        available in a hermetic manner for automatic analysis for the        capacity or until the expiration date as unopened. Other        packages are retained as frozen.    -   4. The calibrating means comprise a functionally hermetic valve        connecting the hermetic control serum package and the liquid        dosing system. Functionally hermetic means that nothing can        enter the hermetic calibrator package, the only flow direction        is out. Technically it can be ensured in a number of ways. A        check valve prevents the backflow and access. A positive        pressure head from the control package ensures a leak out if        any. A closed, hydraulic sampling, e.g. as is used in HPLC or as        described in pre-grant publication US 20040115829 (corresponds        to WO 02/061395 A1), would provide much higher precision than        the pipetting between open liquid surfaces. The benefit is that        the control serum package is functionally unopened and so would        maintain its present working time 2 months, which can be        extended with the system described below. Multiple frozen        packages could be installed within a test unit, having automatic        means of connecting, freezing and thawing to maintain really        long, unattained operation. Since the liquid storing temperature        is critical, temperature stability is monitored and its history        is collected for monitoring. This would enable full automatic        analyzers, “Black-Boxes” (BB), to be used by laymen outside the        laboratory.    -   5. BB-analyzers having the calibration means installed, could        also provided (inter)net connection to centrally monitor all        calibrating result values, done typically in the first most        quiet hours of each day. If any of the calibrating result values        of any test within any test unit is outside the proper values,        the test in that test unit can be centrally turned off or        properly flagged before a work shift starts. It does not matter        if the error is coming from the calibrator liquid, from reagents        or from instrument hardware or from software. The statistical        real time information from the large pool of test units gives a        good statistical tool to handle single exceptional events at the        field automatically via a database.    -   6. In an otherwise good liquid control serum may some components        loose activity over time and some other components maybe        increased from bound to active state. To extend the working time        of a control serum lots in the test units in the field, lots are        carefully monitored centrally for these and other possible small        changes in exactly the same refrigerated conditions than the        calibrator means operate in the field. Any such small but        systematic changes in control values would over time—as        uncorrected—lead to wrong calibration. The central monitoring        the control values is then updating automatically calibrator        values in the field for tests and lots concerned. The working        life of calibrators would be extended, possibly even greatly.    -   7. When a calibrator result value of a test is that way ensured        and a test unit in the field provides a calibrator value outside        the proper range, a “fault” value, it means that reagents are        not working properly because electronic and other measuring        steps are internally controlled and reported OK. If not, the        test unit is automatically replaced in the field. This way the        whole network of test units are successfully monitored, serviced        via network by readjustments or replaced without user's        participation.

The test unit according to the invention is described in the followingin more detail with reference to the drawings, in which

FIG. 1 shows a liquid package in the form of a collapsible bagapplicable in the invention,

FIG. 2 shows an embodiment of the test unit according to the invention,

FIG. 3 shows another test unit according to the invention, and

FIG. 4 shows still another test unit according to the invention.

The invention relates to a test system in clinical chemistry, whichconducts diagnostic tests of liquid samples from a patient, such asblood samples. The system consists of a central control unit, whichpreferably communicates over wireless telecommunications with amultitude of test units remote relative to the control unit. The testunits acting as remote terminals in the system carry out practical testsunder the control and surveillance of the central control unit.

In FIG. 1 there is described as an example a collapsible hermetic liquidpackage 1 in the form of a bag, the liquid being a calibrator liquid, acontrol liquid or a reagent. The control liquid is for instance bloodserum, and the calibrator liquid is a reactive component of blood serum.Other collapsible, sufficiently hermetic bags exist on the market. Sucha bag can consist of two sandwich foils having polyester to outside,aluminum foil in the middle and polyethylene inside. The two sandwichfoils are heat sealed along lines 2 joining inner polyethylene layers. Aheat sealable connecting tube 3 connects the content of the bag 1 toliquid processing system. The top of the package 1 has an opening 4 forhanging the filled bag so that there is a pressure head towards tube 3and towards the liquid processing system of the test unit situatingbelow. Bags can be sterilized and evacuated before filling with controlserums via a tube 3 and after filling hermetically closed for storingand freezing before long term storing.

FIG. 2 shows a test unit providing a hermetic access to refrigeratedcalibrator and control liquids. The unit as shown only comprises theliquid processing section. The rest of the test unit, like electronics,detection, results calculation may be the same as in semiautomaticanalyzers, the most frequent analyzer in the clinical laboratory. Thesection processing liquids is very simple. It has a liquid dosingchamber 5 in the form of an elongated channel closable with valves 6 and7. Above that is a refrigerated liquid storage containing numerousliquid packages 1. There is at least one calibrator liquid package inreservoir 8, at least one control liquid package in reservoir 9 havingworking life at least 2 months in refrigerated liquid, and a number ofreagent packages in reservoir 10 preserving up to two years, as well asother liquid species needed for testing similarly packaged in reservoir10. The reservoir 9 contains an arrangement keeping one control liquid,such as blood serum, bag in a freezer temperature and the others indeep-freezer temperature with programmable, addressable thawing, whenthe time or the capacity of the working bag is expiring. The on-lineaccess to liquid dosing chamber 5 takes place via normally hermeticallyclosed valves 11. Valve 12 provides access to an actuator, which is ahigh precision liquid dispenser, filling hydraulically with pure waterthe chamber 5 between valves 6 and 7. When no air is present, reagentsand control serum can be drawn within the diluent with very highprecision of one nanoliter reproducibility. An inlet conduit 14 for theliquid sample to be tested is connected to the dosing chamber 5 througha valve 11′, working like the other valves 11. It is clear that whenreagents and calibrator and control liquids are boxed in the closed testunit, calibration and controls can be initiated automatically withoutany manual or local operation as programmed e.g. once a day or remotely.Any other valve system, providing high precision and being otherwisesuitable for analytical work, could well be used, too. When all keyliquids determining the quality of analysis can be loaded once or twicea year, it can well be done by professional analyzer service engineersin connection of typical twice a year service visits. When the liquidaccuracy is 20 times higher in the described test unit than inlaboratory analyzers, consumption and size of a test unit according tothe invention can be made correspondingly smaller. Test units withcalibration and control means may be portable or transportable, wherebyonce or twice a year servicing can take place centrally by experts. Whenliquid management is taken care by analyzing personnel taking trips toservice stations and monitoring of quality takes place remotely bydatabases and by professionals, laboratory contributing ⅘ of all IVDcosts is redundant.

In FIG. 3 this invention is applied to a typical clinical analyzer withonly relevant parts of the test unit schematically shown. Analysis takesplace in integrated or individual reaction/measuring cells 13, wheredoses of calibrator and control liquids as well as test samples arerespectively dispensed together with the reagents before mixing,incubation and measurement. The outlet conduit from the valve 7 formsthe dispensing probe 15 to deliver precisely measured control orcalibrator liquids to the measuring cell 13. Calibrator or controlliquid is selected by a proper valve within valve arrays 11, connectingto hermetic test material reservoirs 8-10. For the precise dosing theoutlet valve 7 is closed and an actuator 16, like a syringe as shown ora peristaltic pump, is drawing e.g. under a pressure feed back controlthe dose in chamber 5 and then immediately closing the open valve invalve array 11. The sample inlet conduit 14 and valve 11′ open to thedosing chamber 5 like any of the valves 11. Valve 18 provides connectionto water, used as diluent and for cleaning, to fill the syringe 16.Valve 17 is opened to air for picking air buffers when needed. Water asa system liquid is used to transmit the volumetric changes of theactuator 16. An air buffer is typically arranged between the systemwater and control/calibrator dose, or a sample dose from conduit 14. Thehighest precision in dosing is achieved if the dosing chamber 5 ishydraulically filled to the outlet valve 7 but then a rather largeamount of water diluent must be dispensed together with the calibratoror control liquid or test sample because without air buffer boundaryliquids “telescope” inside each other in a laminar flow. The liquidmaterial reservoirs 8-10 may contain also reagents, but more typical ina laboratory analyzer is that reagents, which form the bulk of testingvolume and typically preserve long even when opened to atmosphere, aredispensed separately to the dosing chamber 5, or to measuring cells 13then constituting dosing spaces, by use of larger dispensers. Then theactuator 16 can be selected for smaller volumes and for higherprecision. When dosing is satisfactory done, valve 7 is opened and theliquid dose is pushed up or with the air buffer. For a higher precisionpart of a known amount of water may also dosed to the measuring cell 13to carry the liquid film left behind by air buffer. Any reagents presentin material reservoirs 8-10 are dosed together with the calibrator orcontrol liquid or with the test sample.

Inventive benefits realize when the control and calibrator liquidpackages are not opened to atmosphere and the dosing takes place in aclosed system where pressure feed back from dosing operations arefeasible, contrary to dosing among open vessels, what contaminate and atthe absence of feedback dosing operations are “blind”. Precisiondetermining control liquid such as control serum thus preserve longon-board and so the manual, variability adding laboratory work withcontrol sera is completely avoided. Automatic analysis based on closed,feed back controlled precision dispensing of long preserving controlmaterials allows remote, networked co-monitoring of control values of alarge number of test units according to the invention. The databaseanalysis provide high precision information of the actual real timeworking values of control materials and so also of reagents, withouttrusting and assuming the nominal short term stable values manufacturersof control sera are providing in the compulsory labelling.

FIG. 4 shows the liquid processing parts of a test unit, which makes adiagnostic test of a liquid medical specimen, such as a blood sampletaken from a patient, by carrying out a test reaction and by detectingthe end result of the reaction. The test unit also performs thenecessary calibrating and control reactions and detects the results in asimilar manner. The test unit comprises an elongated, tubular dosingchamber 5, to which the needle-like suction duct 14 forming the sampleinlet is connected through valve 11′. In addition, the dosing chamber 5is connected with a plurality of liquid packages 1 in liquid storagereservoirs 8-10 through valves 11, there being a reservoir 8 for atleast one calibrator liquid, a reservoir 9 for at least one controlliquid, and a reservoir 10 for reagents. The reagents needed in the testreactions and calibration and control reactions to be performed with thetest unit are stored in the reagent bags in reservoir 10. The test unitis provided with a cooler (not shown) for keeping at least part of thecalibrator liquid, control liquid and reagent packages it theirrespective reservoirs 8-10 freezed, as well as means for selectivethawing of the packages as the liquid is needed for the reactions. Thefeed duct 14 and the connections to each liquid package are equippedwith an on/off valve 11, 11′, and in addition, the dosing chamber 5 isdefined by on/off valves 7, 19, 20. The valves thus determine the volumeof the dosing chamber 5. For dilution of the sample to be tested and thereagents required for the test, the test unit uses water as the medium,and for this purpose the unit is connected to the water mains over apipe 21 equipped with a valve 22. Water is supplied from the pipe 21into a reciprocating bellows 16 acting as an actuator, whichcommunicates over a duct 23 equipped with valves 20, 24 with the dosingchamber 5. The test unit is devised so as to control liquid transfer inall the parts of the unit with suction and expulsion movements generatedby the bellows 16.

An air duct 25 equipped with a valve 26 is connected to said duct 23between the dosing chamber 5 and the bellows 16. This allows the use ofair as a buffer for the transfer of liquids from one part to the otherof the test unit. The duct 23 is additionally equipped with a pressuresensor 27 acting as a sensor, allowing the monitoring of liquidmovements generated with the bellows 16 in different parts of the unit.The sensor 27 detects each starting, arrival to the valve location andstop of the liquid as a pressure variation in the duct system.

At the end opposite to the bellows 16 and to the water and air inlets21, 25, the dosing chamber 5 ends in a valve 7, from where a duct 28continues to the incubation spaces 29 and the detection space 30 formedof a measuring filter trough in the test unit. Adjacent incubationspaces 29 are separated from the duct 28 with on/off valves 31, and thereaction mixture, which is formed in the dosing chamber 5 and consistsof the sample to be tested in these, one or more reagents and wateracting as a medium can be conserved over the period required for therest reaction at a regulated reaction temperature. For mixing associatedliquids in the dosing chamber 5, the duct 28 comprises an expansion 32acting as a mixing chamber. The aligned connections between theincubation spaces 29 are followed by an on/off valve 33 in the duct 28,preceding the measuring filter trough 30, which is equipped with a lightsource 34 and a detector 35. An outlet duct 36 continues from themeasuring filter trough 30 for discharging the liquid used for the testfrom the test unit.

The parts of the test unit used for dosage, calibration, controls, testreaction and result detection need to be cleaned between the tests, andfor this purpose the block is equipped with a detergent liquid inlet 37,which is connected to the dosing chamber 5 and separated from this witha valve 7. The detergent liquid can be discharged from the block into anoutlet duct 36 starting from the measuring filter trough 30.

In the initial situation of the test to be conducted with the test unit,the liquid treatment parts are cleaned and dried, and the valves 7, 11and 19 defining the dosing chamber 5 are closed. The user of the unitconnects the needle-like suction duct 14 acting as the sample inlet tothe sample to be examined and starts the process. The bellows 16 thendraws sample in the duct 14 all the way to the valve 11′, and then thevalve 11′ is closed.

Next, the bellows 16 carries out filling of the dosing chamber 5 withwater acting as a medium, supplied from the water pipe 21. The valve 7after the dosing chamber 5 is opened, and the bellows 16 propels waterthrough the duct 23 into the dosing chamber until the water reaches theopened valve 7. Water entering the valve gap entails a small change ofpressure, which is recorded by the pressure sensor 27, and at thatmoment the automation closes the valve 7. As the filling starts, thevalves 26 and 19 of the air and detergent liquid inlets 25, 37 are alsoopen, so that water propelled by the bellows 16 fills these pipes allthe way to the valves and the pressure sensor 27 causes the valves to beclosed at the moment of filling. As a result of these operations, thedosing chamber 5 is hydraulically filled with water.

At the subsequent sample dosing stage, the valve 11′ of the sample inlet14 is opened, and the bellows 16 draws water from the dosing chamber 5,so that an amount of sample equalling the exhaust suction is sucked fromthe inlet 14 into the dosing chamber. This sample dosing stage ends whenthe valve 11′ of the inlet 14 is closed.

For calibration, calibrator liquid is similarly sucked from a liquidpackage in reservoir 8, by opening the respective valve 11, sucking anamount of calibrator liquid by means of the bellows 16 to the liquiddosing chamber 5, and then closing the valve. For control, an amount ofcontrol liquid is likewise sucked from a liquid package in reservoir 9to the liquid dosing chamber 5, by the valve opening, sucking and valveclosing steps. The calibration and control reactions are then carriedout in the same way as the sample testing, which is described in detailin the following.

Next, one or more reagents needed in the test is dosed accordingly intothe dosing chamber 5. The valve 11 closing the package in the reservoir10 containing the selected reagent is opened, and the bellows 16 drawswater from the dosing chamber 5 so that an amount of water equalling theexhaust suction is drawn into the dosing chamber, after which the valve11 is closed. If more than one reagent is needed, the dosage of thedifferent reagents is carried out one by one with the operationsdescribed above. As a result, the dosed sample and the reagents arebrought into the elongated, tubular dosing chamber 5 in succession,without notable mixing of the liquids at this stage. When the dosage isended, the valve 20 of the dosing chamber 5 facing the bellows is closedand the duct 23 is purged of water by absorption with the bellows 16.

The following stage of the test comprises mixing of the dosed liquidsand mutual reacting of the sample and the one or more reagents. To thisend, the valve 7 after the dosing chamber 5 and the valve 31 connectedwith the selected incubation space 29 are opened, and the dosed liquidsare expelled with the bellows from the chamber 5 into the mixing chamber32, and in conjunction with this, the valve 26 of the inlet 25 is openedin order to use air as a buffer for the liquid transfers produced by thebellows. The liquids are mixed in the chamber 32 with reciprocatingmovements generated by the bellows, and part of the mixed liquid isfurther expelled with the bellows to the measuring filter trough 30 fordetermination of the initial value of measurement. The main portion ofthe liquid is propelled with the bellows into the incubation space 29over the period needed for the test reaction to develop. While thereaction is taking place, the measuring filter trough 30 is cleaned withthe detergent liquid supplied from the pipe 37, the detergent beingpropelled through the dosing and mixing chambers 5, 32 to the measuringfilter trough and further to the outlet duct 36 by means of air suppliedfrom the pipe 25. After the reaction, the reaction mixture is drawn fromthe incubation space 29 to the duct 28 between the dosage space and themeasuring filter trough and is expelled into the filter trough 30 forfinal measurement. After the measurement, the reaction mixture isexpelled by air into the outlet duct 36.

The removal of the reaction mixture after the test from the test unitmay be integrated in the operation of cleaning the unit between thetests. The detergent liquid is supplied from the pipe 37 and is drivenby the bellows 16 with air conducted from the pipe 25 through the dosingchamber 5, the mixing chamber 32 and the measuring filter trough 30 tothe outlet duct 36. Air flows in the centre of the chambers and theducts, and a very small amount of water is enough for cleaning in theform of an air-driven film along the walls of the spaces and the films.The sample inlet 14 is cleaned by opening the valve 11′, so that airpropelled by the bellows drives detergent liquid through the inlet 14out from the liquid test unit.

All of the liquid treatment operations described above take place underautomatic control of the test unit, which is sealed from the environmentwith the exception of said inlets 14, 21, 25 and 37. The result can betransmitted for processing in the central control unit as automatic datatransmission.

In the test unit described above, all the dosages are hydraulicprecision dosages owing to the repetition precision of the movements ofthe bellows 16, the dosages being ensured by means of the pressuresensor 27. The reagents contained in the reagent bags are concentratedstorage solutions, the central control unit being continuously informedof the remaining amounts of reagents. When purged, the reagent and otherliquid bags collapse without requiring replacement air, and theiruncontaminated conservation is ensured in the closed block. By means ofautomation, it can be continually ensured that a vacuum generated by thebellows 16 is prevailing continually while the valves 11 are open, sothat the liquids are merely allowed to flow out from the bags into thedosage space, and never in the opposite direction.

A system comprising a plurality of test units as described aboveconstitutes a network, in which the individual test units are connectedthrough the central control unit. Each test unit has stored in thereservoirs the same calibrator and control liquids and the samereagents. As the number of test units on the field is large, benefitsare gained through production of the various liquids and reagents inlarge batches with reduced manufacturing costs.

Furthermore, the liquids and reagents being the same, the results fromvarious units can be compared, and the control unit will calculateaverages for the results of the calibration and control reactions asreceived from the test units. In this way any errors or anomalies in theresults from any test unit can be instantly recognized, and necessarymeasures can be taken, either as repeated control reactions to detectthe origin of the error or shutting the faulty test unit out ofoperation.

In general the calibration reactions need be performed in the test unitsonly occasionally, particularly when new batches of the various liquidsare taken into use. The control reactions instead are required atfrequent intervals, advantageously every morning before the tests withpatient samples are started, or even every 8 hours for instance. Eachtime the result of the control reaction is compared to the average ofall the test units in the system, to ensure that the unit is in orderand can be used for tests.

In case an error in an individual test unit is detected or suspected,both the calibration and the control reactions are made in the unit. Ifthe result of these two reactions is the same, it reveals that a reagentis spoiled, whereas if the results are different it means that thecontrol liquid is spoiled. All these reactions are carried out in thetest unit automatically under the surveillance of the control unit, andthe only corrective measure to be made manually is to replace the faultyliquid package.

It is obvious to those skilled in the art that the embodiments of theinvention are not confined to the example described in detail above, butmay vary within the scope of the following claims.

1. A method of testing a liquid sample in a test unit comprising aliquid dosing chamber, characterized by provision of at least one closedcalibrator liquid package connected to the dosing chamber through anopenable valve, provision of at least one hermetically closed controlliquid package connected to the dosing chamber through an openablevalve, the control liquid differing from the calibrator liquid,provision of at least one inlet with an openable valve for at least oneliquid reagent, provision of an inlet with an openable valve for theliquid sample to be tested, performing at separate stages calibrating,control and test reactions between the calibrator liquid, control liquidand the liquid sample, respectively, and at least one liquid reagent,each stage comprising opening the respective valves and suckingpredetermined amounts of the reacting liquids to the dosing chamber toproduce the respective reaction, cleaning the dosing chamber between thereactions, registering the results of the calibrating, control and testreactions, and by comparison of said results obtaining a test result forthe liquid sample.
 2. A method according to claim 1, wherein there isprovided at least one closed liquid reagent package connected to thedosing chamber through an inlet with an openable valve.
 3. A methodaccording to claim 1, wherein at each stage before the suckingoperations the dosing chamber is filled with dilution liquid.
 4. Amethod according to claim 3, wherein said sucking operations areeffected by sucking a corresponding amount of dilution liquid from thedosing chamber.
 5. A method according to claim 4, wherein filling theliquid dosing chamber with dilution liquid and sucking dilution liquidfrom the liquid dosing chamber are performed through a commoninlet/outlet connection.
 6. A method according to claim 5, wherein saidfilling and sucking operations are carried out with an actuator actingon the inlet/outlet connection.
 7. A method according to claim 6,wherein said actuator is a bellows, a pump or an injector.
 8. A methodaccording to claim 1, wherein there is a reaction chamber connected withthe dosing chamber through an openable valve, said valve being opened,and the reacting liquids sucked to the dosing chamber being respectivelytransferred to the reaction chamber.
 9. A method according to claim 1,wherein the calibrator liquid package is a sealed collapsible bag with adiminishing volume as liquid is sucked therefrom.
 10. A method accordingto claim 1, wherein the control liquid package is a hermetically sealedcollapsible bag with a diminishing volume as liquid is sucked therefrom.11. A method according to claim 1, wherein the at least one reagentpackage is a sealed collapsible bag with a diminishing volume as liquidis sucked therefrom.
 12. A method according to claim 1, wherein thecontrol liquid is preserved in frozen condition and thawed before it issucked to the dosing chamber.
 13. A method according to claim 1, whereinthe calibrator liquid is preserved in frozen condition and thawed beforeit is sucked to the dosing chamber.
 14. A method according to claim 1,wherein the control liquid is blood serum, and the liquid samples testedare blood-based.
 15. A method according to claim 1, wherein calibratorand/or control liquid reference samples are preserved in circumstancescorresponding to those prevailing in the test unit and analyzed fromtime to time, to estimate the condition of a calibrator and/or controlliquid stored in the test unit.
 16. A method according to claim 1,wherein the calibrating reaction is performed as a new calibrator orcontrol liquid or reagent package is installed in the test unit.
 17. Amethod according to claim 1, wherein the control reaction is performedat regular intervals, preferably at least daily.
 18. A test unit fortesting a liquid sample, characterized in that it comprises a liquiddosing chamber, at least one closed calibrator liquid package connectedto the liquid dosing chamber through an openable valve, at least onehermetically closed control liquid package connected to the liquiddosing chamber through an openable valve, at least one openable inletfor at least one liquid reagent, an openable inlet for a liquid sampleto be tested, an actuator for sucking amounts of said calibrator liquid,said control liquid, said liquid sample and/or said at least one liquidreagent to the liquid dosing chamber at different stages, to performcalibrating, control and test reactions, respectively, and means forregistering and comparing the results of the reactions to obtain a testresult.
 19. A test unit according to claim 18, characterized in that itcomprises at least one closed liquid reagent package connected to theliquid dosing chamber through an inlet with an openable valve, forcombining at least one liquid reagent with the calibrator liquid, thecontrol liquid and the liquid sample, respectively, in the dosingchamber.
 20. A test unit according to claim 18, characterized in that itfurther comprises an openable and closable inlet for filling the liquiddosing chamber with dilution liquid.
 21. A test unit according to claim20, characterized in that it further comprises an openable and closableoutlet for sucking dilution liquid from the liquid dosing chamber.
 22. Atest unit according to claim 21, wherein there is a common inlet/outletconnection for filling the liquid dosing chamber with dilution liquidand sucking dilution liquid from the liquid dosing chamber.
 23. A testunit according to claim 22, wherein said actuator is acting on theinlet/outlet connection for said filling and sucking operations.
 24. Atest unit according to claim 23, wherein said actuator is a bellows, apump or an injector.
 25. A test unit according to claim 18, whereinthere is a reaction chamber connected through an openable valve with thedosing chamber.
 26. A test unit according to claim 18, wherein saidcontrol liquid packages are hermetically sealed collapsible bags with adiminishing volume as liquid is sucked therefrom.
 27. A test unitaccording to claim 18, wherein said calibrator liquid and liquid reagentpackages are sealed collapsible bags with a diminishing volume as liquidis sucked therefrom.
 28. A test unit according to claim 18, whereinthere is a refrigerator for preserving the calibrator and controlliquids in frozen condition and heating means for thawing a selectedcalibrator or control liquid before it is sucked to the liquid dosingchamber.
 29. A test unit according to claim 18, wherein the calibratorliquid is a pure component of blood serum dissolved in a solvent.
 30. Atest unit according to claim 18, wherein the control liquid is bloodserum.
 31. A system containing a plurality of test units for testingliquid samples according to claim 18, characterized in that each testunit is equipped for performing the same test reaction, that the testunits are differently located and each connected through datatransmission communications to a common control unit monitoring the testunits in the system by data transmitted through said communications,that the reaction with the control liquid is performed in each test unitat predetermined time intervals to obtain individual control values forthe test units, an average of said control values of all the test unitsis determined, the individual control values are compared to saidaverage, and only test units with a reference value within a permitteddeviation from the average are approved for performance of the reactionwith samples to be tested.
 32. A system according to claim 31, whereinin test units with a control value outside the permitted deviation fromthe average the reaction with the control liquid is repeated at therequest of the control unit one or more times to exclude the possibilityof a random error.
 33. A system according to claim 31, wherein thereactions with the control liquid are performed at least daily foraccepting daily test results.
 34. A system containing a plurality oftest units for testing liquid samples according to claim 18,characterized in that each test unit is equipped for performing the sametest reaction, that the test units are differently located and eachconnected through data transmission communications to a common controlunit monitoring the test units in the system by data transmitted throughsaid communications, that the performance of said test system is fromtime to time independently evaluated by an accurate analysis of controland calibrator liquid reference samples preserved in circumstancescorresponding to those prevailing in the test units, to estimate andadjust the time effect on calibrator and on control liquids and onreagents stored in the test units.